Qt creator

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_Register_Button_clicked()
{
    ShellExecute( NULL, L"open", L"http://www.mpcforum.pl/", L"", L"", SW_SHOWNORMAL );
}

void MainWindow::on_Login_Button_clicked()
{
    QString username;
    QString password;

    username = ui->Username_Form->text();
    password = ui->Password_Form->text();

    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
    db.setHostName("localhost");
    db.setDatabaseName("testdb");
    db.setUserName("root");
    db.setPassword("rootpassword");
}